Symptoms of severe asthma: respondents with current wheeze who had ⩾4 attacks of wheeze in the last year or had ⩾1 nights per week sleep disturbance from wheeze in the last year or had wheeze affecting speech in the last year.

*Number of children. †The data presented are restricted to respondents who answered “yes” to the question about current wheeze. ‡Centres in Australia, Canada, Isle of Man, New Zealand and the UK.